shader: rely on the saturating float-to-int conversion instead of re-saturating in the translator

This commit is contained in:
nmzik
2026-10-22 00:26:40 +02:00
parent 3bb09ed2a4
commit 2d00e13bf3
3 changed files with 18 additions and 58 deletions
@@ -6,38 +6,6 @@ IR::F32 Translator::SelectF32(IR::U1 condition, IR::F32 true_value, IR::F32 fals
return IR::F32(ir.Emit(IR::ValueOpcode::SelectF32, {condition, true_value, false_value}));
}
IR::U32 Translator::ConvertF32ToU32Saturated(IR::F32 value, float upper_bound, float safe_upper,
uint32_t upper_result) {
const auto zero = IR::F32(IR::Value::F32(0.0f));
const auto nan = IR::U1(ir.Emit(IR::ValueOpcode::FPIsNan32, {value}));
const auto low = IR::U1(ir.Emit(IR::ValueOpcode::FPOrdLessThanEqual32, {value, zero}));
const auto high = IR::U1(
ir.Emit(IR::ValueOpcode::FPOrdGreaterThanEqual32, {value, IR::Value::F32(upper_bound)}));
const auto truncated = IR::F32(ir.Emit(IR::ValueOpcode::FPTrunc32, {value}));
const auto safe_low = SelectF32(ir.LogicalOr(nan, low), zero, truncated);
const auto safe = SelectF32(high, IR::F32(IR::Value::F32(safe_upper)), safe_low);
const auto converted = IR::U32(ir.Emit(IR::ValueOpcode::ConvertU32F32, {safe}));
return ir.Select(high, IR::U32(IR::Value(upper_result)), converted);
}
IR::U32 Translator::ConvertF32ToI32Saturated(IR::F32 value, float lower_bound, float upper_bound,
float safe_upper, uint32_t lower_result,
uint32_t upper_result) {
const auto nan = IR::U1(ir.Emit(IR::ValueOpcode::FPIsNan32, {value}));
const auto low = IR::U1(
ir.Emit(IR::ValueOpcode::FPOrdLessThanEqual32, {value, IR::Value::F32(lower_bound)}));
const auto high = IR::U1(
ir.Emit(IR::ValueOpcode::FPOrdGreaterThanEqual32, {value, IR::Value::F32(upper_bound)}));
const auto truncated = IR::F32(ir.Emit(IR::ValueOpcode::FPTrunc32, {value}));
const auto safe_low = SelectF32(low, IR::F32(IR::Value::F32(lower_bound)), truncated);
const auto safe_high = SelectF32(high, IR::F32(IR::Value::F32(safe_upper)), safe_low);
const auto safe = SelectF32(nan, IR::F32(IR::Value::F32(0.0f)), safe_high);
const auto converted = IR::U32(ir.Emit(IR::ValueOpcode::ConvertS32F32, {safe}));
const auto clamped_high = ir.Select(high, IR::U32(IR::Value(upper_result)), converted);
const auto clamped = ir.Select(low, IR::U32(IR::Value(lower_result)), clamped_high);
return ir.Select(nan, IR::U32(IR::Value(0u)), clamped);
}
void Translator::V_CVT_F32_UBYTE(const Decoder::Instruction& inst, uint32_t byte_index) {
const auto source = ReadU32(SourceAt(inst, 0));
const auto byte =
@@ -58,15 +26,12 @@ void Translator::V_CVT_F32_I32(const Decoder::Instruction& inst) {
void Translator::V_CVT_U32_F32(const Decoder::Instruction& inst) {
const auto value = IR::F32(ReadOperand(SourceAt(inst, 0), IR::Type::F32));
WriteOperand(DestinationOperand(inst),
ConvertF32ToU32Saturated(value, 4294967296.0f, 4294967040.0f, 0xffffffffu));
WriteOperand(DestinationOperand(inst), ir.Emit(IR::ValueOpcode::ConvertU32F32, {value}));
}
void Translator::V_CVT_I32_F32(const Decoder::Instruction& inst) {
const auto value = IR::F32(ReadOperand(SourceAt(inst, 0), IR::Type::F32));
WriteOperand(DestinationOperand(inst),
ConvertF32ToI32Saturated(value, -2147483648.0f, 2147483648.0f, 2147483520.0f,
0x80000000u, 0x7fffffffu));
WriteOperand(DestinationOperand(inst), ir.Emit(IR::ValueOpcode::ConvertS32F32, {value}));
}
void Translator::V_CVT_F16_F32(const Decoder::Instruction& inst) {
@@ -86,31 +51,30 @@ void Translator::V_CVT_F16_16(const Decoder::Instruction& inst, bool signed_valu
void Translator::V_CVT_16_F16(const Decoder::Instruction& inst, bool signed_value) {
const auto value = ReadF16AsF32(inst.src0);
// The 32-bit conversion already saturates and maps NaN to zero.
if (signed_value) {
const auto converted =
ConvertF32ToI32Saturated(value, -32768.0f, 32768.0f, 32767.0f, 0xffff8000u, 0x7fffu);
Write16Bits(DestinationOperand(inst), converted);
const auto converted = ir.Emit(IR::ValueOpcode::ConvertS32F32, {value});
const auto low = ir.Emit(IR::ValueOpcode::SMax32, {converted, IR::Value(0xffff8000u)});
Write16Bits(DestinationOperand(inst),
IR::U32(ir.Emit(IR::ValueOpcode::SMin32, {low, IR::Value(0x7fffu)})));
return;
}
const auto converted = ir.Emit(IR::ValueOpcode::ConvertU32F32, {value});
Write16Bits(DestinationOperand(inst),
ConvertF32ToU32Saturated(value, 65536.0f, 65535.0f, 0xffffu));
IR::U32(ir.Emit(IR::ValueOpcode::UMin32, {converted, IR::Value(0xffffu)})));
}
void Translator::V_CVT_RPI_I32_F32(const Decoder::Instruction& inst) {
const auto source = IR::F32(ReadOperand(SourceAt(inst, 0), IR::Type::F32));
const auto biased = IR::F32(ir.Emit(IR::ValueOpcode::FPAdd32, {source, IR::Value::F32(0.5f)}));
const auto rounded = IR::F32(ir.Emit(IR::ValueOpcode::FPFloor32, {biased}));
WriteOperand(DestinationOperand(inst),
ConvertF32ToI32Saturated(rounded, -2147483648.0f, 2147483648.0f, 2147483520.0f,
0x80000000u, 0x7fffffffu));
WriteOperand(DestinationOperand(inst), ir.Emit(IR::ValueOpcode::ConvertS32F32, {rounded}));
}
void Translator::V_CVT_FLR_I32_F32(const Decoder::Instruction& inst) {
const auto source = IR::F32(ReadOperand(SourceAt(inst, 0), IR::Type::F32));
const auto rounded = IR::F32(ir.Emit(IR::ValueOpcode::FPFloor32, {source}));
WriteOperand(DestinationOperand(inst),
ConvertF32ToI32Saturated(rounded, -2147483648.0f, 2147483648.0f, 2147483520.0f,
0x80000000u, 0x7fffffffu));
WriteOperand(DestinationOperand(inst), ir.Emit(IR::ValueOpcode::ConvertS32F32, {rounded}));
}
void Translator::V_FREXP_EXP_I32_F32(const Decoder::Instruction& inst) {
@@ -157,7 +121,9 @@ void Translator::V_CVT_PKNORM_F32(const Decoder::Instruction& inst, IR::ValueOpc
void Translator::V_CVT_PK_U8_F32(const Decoder::Instruction& inst) {
const auto source = IR::F32(ReadOperand(SourceAt(inst, 0), IR::Type::F32));
const auto byte = ConvertF32ToU32Saturated(source, 255.0f, 255.0f, 255u);
const auto byte =
IR::U32(ir.Emit(IR::ValueOpcode::UMin32,
{ir.Emit(IR::ValueOpcode::ConvertU32F32, {source}), IR::Value(255u)}));
const auto index = ir.BitwiseAnd(ReadU32(SourceAt(inst, 1)), IR::U32(IR::Value(3u)));
const auto shift = ir.ShiftLeftLogical(index, IR::U32(IR::Value(3u)));
const auto mask = ir.ShiftLeftLogical(IR::U32(IR::Value(0xffu)), shift);
@@ -113,11 +113,6 @@ private:
void DS_ORDERED_COUNT(const Decoder::Instruction& inst);
IR::F32 SelectF32(IR::U1 condition, IR::F32 true_value, IR::F32 false_value);
IR::U32 ConvertF32ToU32Saturated(IR::F32 value, float upper_bound, float safe_upper,
uint32_t high_result);
IR::U32 ConvertF32ToI32Saturated(IR::F32 value, float lower_bound, float upper_bound,
float safe_upper, uint32_t lower_result,
uint32_t upper_result);
IR::U32 PackU16Lanes(IR::U32 low, IR::U32 high);
void EmitCompareResult(const Decoder::Instruction& inst, IR::U1 value, bool scalar, bool cmpx);
void EmitCompareConstant(const Decoder::Instruction& inst, bool value, bool scalar, bool cmpx);
@@ -837,12 +837,11 @@ bool SrtWalker::EvaluateInst(const Inst& inst, uint64_t& result) {
return false;
case ValueOpcode::ConvertU32F32:
if (Arg(inst, 0, a)) {
// The conversion saturates and maps NaN to zero.
const auto value = Float32(a);
if (!std::isfinite(value) || value < 0.0f ||
static_cast<double>(value) > UINT32_MAX) {
return false;
}
result = static_cast<uint32_t>(value);
result = std::isnan(value) || value <= 0.0f ? 0u
: value >= 4294967296.0f ? UINT32_MAX
: static_cast<uint32_t>(value);
return true;
}
return false;